Brain Delay: Air pollutants linked to slow childhood mental development

Pollutants spewing from vehicles and power plants may be harmful to fetal brains, new evidence suggests. The study is the first to directly link delayed cognitive development in children to their mothers' exposure during pregnancy to common air pollutants called polycyclic aromatic hydrocarbons, or PAHs.

Earlier studies established a similar relationship between slowed neurological development and prenatal exposure to lead, says Frederica P. Perera, the Columbia University environmental health scientist who led the new study.